Single zone won't shut off unless I shut off irrigation water main

Hi all. Been stressed about this for a week now, so would really appreciate if someone can please lend some insight.

Have a smart controller, RainMachine HD-16. Worked fine last year.
Have 13 zones with 4-5 sprinklers a piece. 6 zones in front of the house, 7 zones in back.
Have a valve controller box (outdoor) with just 3 Hunter SRV valves in them in the backyard, where all the wires from the irrigation controller (indoors) are wired to. Not sure if 3 sprinkler valves are enough for my property, but its the only box in the ground I've seen anywhere (prior owner doesn't know if there are others).

When opening the sprinklers this year, there is one zone in the backyard that is stuck on and won't shut off. They remain on in conjunction with any other zones that are selected.

I checked the 3 irrigation valve controllers, and cleaned them all up. No diaphragms broken. Tightened all the solenoids. Even unplugged power to the Rainmachine irrigation controller. Problem persisted. The only way I could shut off the sprinkler was by cutting the main water source.

Today, I opened up the water again, and tried switching to a zone in front of the house, and now a zone in the front yard is stuck open. The one in the back that was stuck before, now starts and stops fine. The only way I could shut off the sprinkler again, was to cut off via the irrigation water main.

Any ideas? I wonder why just a single zone is stuck open and not every other zone on that same irrigation controller?
Also, it's very odd that a zone in the backyard is stuck, and now the problem has moved to the front, at least 100 yards away.

ONE other note, my wife had a landscaper move some plants a few weeks ago. 3 poly irrigation pipes broke as a result. I repaired them, but found that a thick gauged wire has had the outer jacket/shielding cut a bit, likely from their shovel. The wires underneath don't look damaged though.

Ok, had no choice but to call someone in today. I absolutely had more than just those 3 zones in the valve box I found. THe others are littered randomly throughout my yard. Finding them is what I had to pay for, so I ended up paying 3 guys to search around my 1 acre.

Luckily, the irrigation guys found a valve controller near a garden bed, and that was the one that was stuck. He opened the valve, the rock or pebble etc blew out, and problem solved.

While they were here, they also addressed the wiring issue, by using simple electrical tape around each of the wires that had shielding severed by the landscapers' shovel.

All in all, a simple fix I could have done myself, but alas, I did not know where to find those valve boxes buried randomly around the yard in no boxes that are visible...